A computer network is a collection of interconnected computing devices that can exchange data and share resources. Often, in highly populated areas, the computer network is configured in a ring formation, where certain devices, referred to as “switches,” are interconnected via network links in the shape of a ring. That is, each switch couples via a separate network link to two adjacent switches, one clockwise and the other counter-clockwise around the ring. When shaped in a ring, the optical fiber network is referred to as a “ring network.”
Generally, the switches provide access to the ring network. The computing devices couple to the switches to gain access to the ring network and thereby interconnect with other computing devices coupled to the ring network. The computing devices generate data traffic and exchange this data traffic with other computing devices via the interconnection provided by the ring network. The switches forward the data traffic typically in a determined direction, e.g., clockwise or counter-clockwise, around the ring to facilitate the exchange. The ring network may provide generous geographical coverage due to its shape, which allows the ring network to reach computing devices dispersed over wide geographical areas. The ring network may be resilient in that it can forward data in both the clockwise and counter-clockwise directions to avoid a faulted link.
While providing generous geographical coverage and reasonable resilience, the ring network may suffer from traffic loops. For certain types of data that do not include a specific destination, such as multicast or broadcast data, for example, each of the switches may simply forward this data around the ring to ensure each switch forwards the ring to every computing device. If none of the switches identify that this data is looping the ring network, each switch may continue to forward the traffic endlessly, thereby establishing a traffic loop, which may substantially impact the performance of the ring network by needlessly consuming network resources, such as switch processing time and memory as well as link bandwidth.
Some ring networks, however, implement network management techniques to correct for traffic loops. One such network management technique, for example, may designate one of the devices of the ring network as a master device, where the master device includes a primary port and a secondary port. The master device forwards traffic via the primary port and blocks traffic via the secondary port. Typically, the master device blocks the secondary port logically. In other words, the master device may actively filter traffic arriving via the secondary port, discarding or dropping certain traffic, such as data traffic, but allowing other traffic, such as control traffic used by the master device to monitor or otherwise control the ring network. By blocking traffic arriving via the secondary port in this manner, the master device ensures that data traffic does not continually loop the ring network, while preserving the beneficial aspects of generous geographical coverage and resilience associated with the ring network.